A vast "island universe" of stars, gas, and dust. The universe may contain 100 billion or more galaxies. Galactic size and structure range from dwarfs and irregulars with no discernible structure and only a few million stars to giant spirals and ellipticals that span 100,000 light-years or more and contain hundreds of billions of stars. Galaxies clump together in web-like structures. Despite its great luminosity, most of a galaxy's mass consists of dark matter, which produces no detectable energy.


Galaxies Fade Eventually, the stars of the Milky Way will burn...
Types of Galaxies Galaxies can be classified in several ways. The...
Galaxies: Cities of Stars Stars beyond counting populate the universe....

Radio Programs

Tadpole Galaxies The inside-out heads of tadpole galaxies Friday, November 28, 2014
Great Wall A wall of galaxies across the universe Monday, November 17, 2014
Maffei 1 A bright galaxy hides behind a veil of dust Saturday, October 4, 2014
Powerful Jets Powerful jets from massive black holes Tuesday, August 12, 2014
Magellanic Clouds A new view of two close neighbors Monday, July 14, 2014
Leo T A tiny galaxy with bright ambitions Sunday, May 25, 2014
Supernova Factory A galaxy with a steady supply of fireworks Tuesday, March 25, 2014
Condor Galaxy The condor stretches its galactic wings Saturday, March 15, 2014
Triangulum Galaxy A galaxy that’s losing its identity Sunday, November 10, 2013
Andromeda Galaxy III Building a galactic giant Saturday, November 9, 2013
Galactic Thief A case of galactic thievery Saturday, June 15, 2013
M101 A beautiful galactic neighbor Friday, May 31, 2013
GALEX Keeping an eye on the galactic action Sunday, April 28, 2013
Coma Galaxy Cluster A brilliant cluster of galaxies Friday, April 19, 2013
Quasars II Lighting up a distant galaxy Wednesday, February 6, 2013
IC 10 A faint but busy galactic neighbor Monday, October 8, 2012
BL Lacertae A star that’s more than a star Friday, September 14, 2012
Andromeda Starburst Brightening up a giant galaxy Thursday, September 13, 2012
The Sombrero II Two galaxies for the price of one Tuesday, July 3, 2012
The Sombrero Looking beneath the brim of a galaxy Monday, July 2, 2012
Galactic Streams Blending into the Milky Way Thursday, March 22, 2012
Sagittarius Dwarf A galactic tug-of-war Wednesday, March 21, 2012
Satellite Galaxies Satellite galaxies for the Milky Way Tuesday, March 20, 2012
IC 342 A close but veiled cosmic pinwheel Sunday, January 22, 2012
M83 Livening up the galactic boondocks Tuesday, April 26, 2011
Sunflower Galaxy A good night for galaxy-watching Thursday, March 31, 2011
Galaxies and Black Holes Insight into a chicken-and-egg problem Tuesday, March 8, 2011
Galactic Pileup A big galactic pileup Saturday, January 15, 2011
Palomar 1 The Milky Way destroys a star cluster Saturday, December 4, 2010
Galactic Leaders The leaders of a galactic pack Friday, November 5, 2010
Herculean Galaxies Stirring up spiral galaxies Friday, October 1, 2010
Galactic Bubbles Blowing bubbles in the Milky Way Tuesday, August 10, 2010
Dark Matter Particle Big, heavy, but hard to find Wednesday, July 21, 2010
Immigrant Clusters Invaders from other galaxies Wednesday, July 7, 2010
Galactic Melting Pot Building a "cosmopolitan" galaxy Tuesday, July 6, 2010
M101 Outlining a perfect cosmic pinwheel Sunday, June 13, 2010
M81 A "grand design" for a galaxy Saturday, June 12, 2010
Galactic Bridge Building a bridge between galaxies Monday, March 15, 2010
More M87 Illuminating a galaxy's darkness Thursday, May 14, 2009
M87 A galaxy piles up the zeroes Wednesday, May 13, 2009
Building Galaxies Black holes and galactic bulges Wednesday, April 29, 2009
Tough Neighborhood Growing up in a tough neighborhood Monday, April 27, 2009
Black-Eye Galaxy A galaxy gets a real shiner Saturday, April 11, 2009
Hanny's Voorwerp The echo of a dead quasar Thursday, March 12, 2009
Galaxy Zoo Sorting out the galactic zoo Wednesday, March 11, 2009
Largest Void A giant "hole" in the universe Wednesday, February 18, 2009
First Supercluster Big clumps in the universe Tuesday, February 17, 2009
Back in the Empire A galactic colony returns to the fold Thursday, January 15, 2009

Featured Images

Hubble Space Telescope view of Tadpole Galaxy
Galactic Tadpole Thursday, November 27, 2014
NGC 1398, a spiral galaxy in the constellation Fornax
Strangely Familiar Saturday, August 23, 2014
Jetting Across the Universe Tuesday, August 12, 2014
A view of the busy Milky Way
Busy Galaxy Thursday, July 24, 2014
Magellanic clouds above the ALMA radio telescope array
Cloudy Neighbors Monday, July 14, 2014
Combined visible, X-ray image of M51, the whirlpool galaxy
Colorful Whirlpool Wednesday, June 4, 2014
HST image of thousands of galaxies
Galaxies Galore Thursday, April 17, 2014
The Condor galaxy
Night of the Condor Saturday, March 15, 2014
Hubble Space Telescope view of M83 galaxy
Glowing Pinwheel Friday, January 10, 2014
Telescopic view of M33, the Triangulum Galaxy
Pirouetting Octopus Sunday, November 10, 2013
Ultraviolet view of spiral galaxy NGC 6744 from the GALEX spacecraft
End of the Line Saturday, June 29, 2013
Hubble Space Telescope image of M101
Stellar Pinwheel Friday, May 31, 2013
Hubble view of Coma Cluster of galaxies
Crowning Glory Friday, April 19, 2013
The Antennae galaxies
Getting Together Tuesday, April 16, 2013
Artist's concept of a distant quasar
Fiery Galaxy Tuesday, February 5, 2013
Hubble image of an edge-on galaxy, ESO 318-13
All that Glitters Tuesday, December 4, 2012
The nearby starburst galaxy IC 10
Active Neighbor Monday, October 8, 2012
Portion of Hubble Extreme Deep Field
Extreme Astronomy Tuesday, September 25, 2012
Andromeda and the Milky Way head for a galactic pile-up
Collision Course Wednesday, September 12, 2012
Hubble image of a pair of galaxies
Bright Companions Friday, September 7, 2012
Hubble Space Telescope view of M104, the Sombrero Galaxy
Galactic Hat Dance Monday, July 2, 2012
The remnants of two merged galaxies
Fast Exit Monday, June 18, 2012
Star Stream Tuesday, May 15, 2012
Combined X-ray, optical, and radio view of the galaxy Centaurus A
Busy Galaxy Sunday, April 29, 2012
Space-based infrared view of the Large Magellanic Cloud
Busy Neighbor Tuesday, March 20, 2012
Optical and X-ray image of the galaxy cluster Abell 383
Brilliant Darkness Friday, March 16, 2012
New Heavyweight Champion Monday, February 6, 2012
Infrared view of the spiral galaxy IC 342
Tangled Galaxy Sunday, January 22, 2012
Galactic Swirl Wednesday, December 14, 2011
NGC 4438 and NGC 4435, galaxies in Virgo
Beautiful Eyes Thursday, August 25, 2011
NGC 3758, a system of two merging galaxies
Double Trouble Saturday, June 11, 2011
X-ray and radio image of galaxy M87
Close to the Monster Thursday, March 10, 2011
Irregular galaxy Henize 2-10, which appears to contain a supermassive black hole
Small But Powerful Tuesday, March 8, 2011
Spiral galaxy NGC 3621 in the constellation Hydra
Galactic Sparkler Wednesday, February 2, 2011
NGC 7252, aka the Atoms-for-Peace galaxies
Atomic Pile-up Saturday, November 20, 2010
Six Spiral Galaxies from European Southern Observatory
Galaxies Galore Friday, October 29, 2010
Ground-based image of the galaxy cluster Abell 2151, in Hercules
Galaxies Galore Friday, October 1, 2010
NGC 4666, a starburst galaxy
Lively Galaxy Friday, September 3, 2010
M87 black hole
Busy Black Hole Wednesday, August 11, 2010
Galactic Beauty Wednesday, August 11, 2010
This giant cluster of galaxies and hot gas provides evidence of dark matter.
Cosmic Bullets Tuesday, July 20, 2010
An ultraviolet view of the spiral galaxy M81 shows young, hot stars in blue and
Grand Galaxy Saturday, June 12, 2010
Beautiful Triplets Monday, March 8, 2010
Starry Neighbor Friday, February 26, 2010
Mini Us Friday, November 27, 2009
Bursting with Starbirth Monday, November 9, 2009
A Big Shiner Saturday, April 11, 2009
Galactic Turmoil Monday, March 23, 2009
Jetting Away Thursday, November 20, 2008
Getting Hitched Friday, June 27, 2008
Home Base Wednesday, June 4, 2008
Galactic Giant Friday, May 9, 2008
Crowded Neighborhood Thursday, May 8, 2008
Sharper View Wednesday, May 7, 2008
Glowing Galaxies Tuesday, May 6, 2008
Galaxies Galore Monday, May 5, 2008
Galactic Embrace Thursday, May 1, 2008
Galactic Glow Friday, February 8, 2008
Under Attack Tuesday, December 18, 2007
Triangular Spiral Monday, November 19, 2007
Mingling Galaxies Thursday, November 15, 2007
Cartwheeling Through Space Saturday, November 10, 2007
Virgo Cluster Monday, July 2, 2007
Galactic Pinwheel Wednesday, June 6, 2007
Galactic Trainwreck Tuesday, April 17, 2007
Galactic Beauty Saturday, April 7, 2007
Spectacular Spiral Wednesday, April 4, 2007
Galactic Beauties Thursday, February 8, 2007
Sweeping Beauty Sunday, January 21, 2007
Galactic Fireworks Tuesday, November 28, 2006
Jetting Away from a Black Hole Thursday, November 9, 2006
Popping Off Friday, October 27, 2006
Lighting up the Darkness Tuesday, October 3, 2006
Galactic Empire Tuesday, September 19, 2006
New View of a Neighbor Sunday, September 10, 2006
Psychedelic Gas Friday, June 16, 2006
Smokin' Galaxy Wednesday, May 24, 2006
Bright Spider Tuesday, May 16, 2006
Efficient Black Hole Tuesday, April 25, 2006


©2014 The University of Texas McDonald Observatory